One part of town that has seen persistent homeless encampments over the past year is the area around Cesar Chavez and the 101/Potrero interchange, sometimes referred to as "The Hairball." About 100 people had set up camp there when the city cleared the area last May, and in the months since then, particularly during inclement weather, tents have clustered under overpasses and blocked the pedestrian and bike bridge there many times, as Streetsblog SF tells us, often creating a hazardous situation for bicyclists who in earlier years here only had to worry about not getting hit by a speeding car.
Sam Dodge, Deputy Director of the Department of Homelessness & Supportive Housing for San Francisco, tells the site that the area has been a refuge for people for about 20 years, and one commenter says that recent crackdowns by the city, including new fencing around some of the overpasses, have caused more people to set up camp on the bike paths themselves. And while most try to keep their tents to one side, this does often make for narrow squeezes for cyclists, some of whom tell the site they just avoid using the paths altogether if they can help it.
The dirt below the ramps is Caltrans property, while the bike bridges are city property, and reportedly when camps are cleared from one area or the other, they just shift from below the ramps to on top of them. (And as one Redditor commented several months back, s/he witnessed a tarp one draped from side to side on the bike path, turning one entire section of it into an ersatz shelter with "dozens of bikes" inside it.)
Dodge said he was sending out a homeless outreach team and Public Works to again address the issue, but it seems as though this is a part of the city that has belonged to campers for too long, and bicyclists have mostly ceded the territory.
Back in 2014, the SF Bicycle Coalition and Streetsblog celebrated the transformation of The Hairball into a calmer and safer place for bicyclists, largely because of this newly built bicycle infrastructure, but it doesn't do them much good now if they're swerving around people and animals and potentially colliding with encampments (or people) as they try to pass through.